1. Field of the Invention
The invention generally relates to vision correction through laser treatment of the eye, and more specifically to a method of pretesting a laser treatment by first performing the treatment on a contact lens that is then worn by the patient.
2. Description of the Related Art
The field of corrective eye surgery has seen remarkable advances over the past two decades. Eye surgeons have sought and developed solutions for vision correction more permanent than prosthetic devices such as glasses and contact lenses. The initial surgical techniques employed RK, or radial keratotomy, in which the surgeon used a blade to make incisions in the eye, causing the cornea to flatten or steepen in desired directions. This procedure has been largely supplanted by the use lasers, especially excimer lasers, to actually shape the cornea in a technique known as PRK, or photo-refractive keratectomy. This technique literally resculpts the cornea of the eye using an excimer, "cold light" laser that removes material without significantly heating stromal tissue. A variety of techniques have been developed using these lasers, including scanning technologies, fixed and variable spot size technologies, erodible mask technologies, and the ablation of the subsurface of the cornea in a technique known as LASIK, or laser in situ keratomileusis. Some of these techniques and systems for practicing them are further described in U.S. patent application Ser. No. 08/324,782, filed Oct. 18, 1994, entitled "Excimer Laser System for Correction of Vision with Reduced Thermal Effects"; U.S. patent application Ser. No. 08/338,495, filed Nov. 15, 1994, entitled "Apparatus for Modifying the Surface of the Eye Through Large Beam Laser Polishing and Method of Controlling the Apparatus"; and U.S. Pat. No. 4,840,175 to Peyman, issued Jun. 20, 1989, entitled "Method for Modifying Corneal Curvature," all of which are hereby incorporated by reference.
All of these systems, however, demand precision--although follow-up surgeries can be performed, once the tissue is removed, it is permanently removed. Therefore, it is highly desirable that a treatment pattern developed for one of these systems be accurate. To this end, a technique would be desirable for pretesting a treatment pattern before actually performing that treatment pattern on the patient's eye.